With the development of mobile Internet and Internet of Things (IoT), demands on traffic data volume have increased explosively, and mobile communication techniques have been confronted with a new technical challenge from connections among a large amount of devices and diversified IoT services. Time delay and reliability of conventional communication systems are designed with respect to communication among humans. Besides continuing to satisfy demands on the communication among humans in terms of the time delay and the reliability, a future wireless communication system also needs to meet real-time and reliability required by Machine Type Communication (MTC), so as to facilitate new applications in industrial fields such as Transportation Security, Transportation Efficiency, Smart Grids and thereby to make concepts of future smart society and smart planet possible. New application fields require higher performance of the future wireless communication system.
Table 1 shows standards for a Quality of Service (QoS) Class Identifier (QCI) defined by a 3rd Generation Partnership Project (3GPP). As shown in Table 1, in the conventional wireless communication system, transmission reliability in case of a stringent requirement on the time delay is usually 10−2 to 10−3. For services having a stringent requirement on the reliability, the requirement on the time delay is usually not so strict. Even the most stringent requirement on the time delay is 100 ms for a conversational service, and is 50 ms for a real-time gaming service.
TABLE 1QCI for a Long Term Evolution (LTE) systemResourcePriorityPacketPacketService QCITypeleveldelayerror rateapplication1GBR2100 ms10−2Conversational (GuaranteedVoice2Bit Rate)4150 ms10−3Conversational Video(Live Streaming)33 50 ms10−3Real Time Gaming45300 ms10−6Non-ConversationalVideo (BufferedStreaming)5Non-GBR1100 ms10−6IMS Signalling6(Non6300 ms10−6Video (BufferedGuaranteedStreaming)Bit Rate)TCP-based (e.g., www, e-mail, chat, ftp, p2p filesharing, progressivevideo, etc.)77100 ms10−3Voice,Video (Live Streaming)Interactive Gaming88300 ms10−6Video (BufferedStreaming)TCP-based (e.g., www, e-mail, chat, ftp, p2p file99sharing, progressivevideo, etc.)
With continuous emergence of new applications such as remote industrial control and augmented reality, requirements on the wireless communication system are higher than ever before.
However, the real-time property and the reliability in the conventional wireless communication system are relatively low, and cannot meet the real-time property and the reliability required by new applications such as MTC.